VIENNA -- A biomarker of acute kidney injury was predictive of worse outcomes at 3 months in one ischemic stroke model, but not in another, researchers reported here.

Plasma concentrations of the protein neutrophil gelatinase-associated lipocalin (NGAL) at 1 week were associated with worse outcomes when added to a model assessing NIH stroke score, age, thrombolysis, and estimated glomerular filtration rate (eGFR) (P=0.048), according to Thomas Seifert-Held, MD, of the Medical University of Graz in Austria, and colleagues.

However in a model that included post-stroke infection, concentrations of NGAL offered no predictive value in patient outcomes, Seifert-Held told MedPage Today at a poster presentation during the World Congress of Neurology.

Plasma NGAL can be used to determine acute kidney injury, its severity, and distinguish it from reversible transient kidney dysfunction in emergency departments. The authors also noted that elevated NGAL levels in peripheral blood have been associated with 6-month mortality in patients who suffered ischemic and hemorrhagic stroke.

"Brain ischemia elicits systemic immunodepression, which promotes post-stroke infectious diseases," they wrote, adding that such events are common to one in three stroke patients and can impair long-term recovery.

Participants were included if they had a diagnosis of ischemic stroke based on clinical examination or brain MRI, if they had an NIH stroke score of greater than 3 at admission, and if they had a Modified Rankin Scale (mRS) of 0 or 1 before symptom onset. They were excluded if there was already evidence of infectious disease at admission.

Patient outcomes were assessed through mRS at 90 days after stroke incidence and were obtained by phone interview with the patient or their caregivers. They also had estimated glomerular filtration rate (eGFR) assessed through a blood sample taken at a median 7 days from the stroke.

Researchers recorded post-stroke infection that required antibiotic treatment and was confirmed through clinical, radiological, or laboratory tests. Patients did not receive preventive antibiotics.

Participants had a median NIH stroke score of 11 at admission and a median mRS of 3 at 90 days after admission.

Additionally, patients with post-stroke infection had significantly higher NGAL concentrations than those who had no infection (86.4 ng/mL versus 43.4 ng/mL, P=0.006).

The authors then developed predictive models of stroke outcome based on mRS, eGFR, age, and thrombolytic therapy in one model, and infection in lieu of eGFR in a second model. Then they added concentration of NGAL to each model to determine the effect of its concentration on functionality outcomes.

In models without infection and with NGAL, the area under the curve (AUC) was significantly more predictive of patient outcomes than in a model without NGAL (AUC 0.935, 95% CI 0.864-1.000 versus AUC 0.851, 95% CI 0.743-0.958, P=0.048). However, this association was not significant when infection was included.

Seifert-Held also noted that their study was the first to establish this relationship in ischemic stroke patients.

The authors declared no conflicts of interest.

Reviewed by Zalman S. Agus, MD Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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